What do you mean, setting screen size with a verb? If so, that's very much possible.
I think what he means is to have the game screen placed inside a browser window so the screen can be larger than it is. Although I don't really see much point in that myself.
the file doesn't seem to still be up there, but it sounds like what you might be looking for. it would display the contents of DS's display area in a separate window that could be resized, so you could make it fullscreen. you're still displaying what BYOND displays, so it can only go up to 21x21 tiles.